Question

What is the determining factor for the transcription of structural genes of the trp operon?
A. the quantity of trp repressor protein made by the regulatory gene trpR
B. the ability of RNA polymerase to bind to the promoter region
C. the availability of tryptophan in the environment
D. the location of a regulatory gene with reference to the other regions of the operon
E. the activity of the other operons present in bacteria

Answer 1

c is the answer but i only guess

Answer 2

Answer

A. the quantity of trp repressor protein made by the regulatory gene trpR

Explanation:

The structural genes of the trp operon are labeled e, d, c, b, and a. RNA polymerase transcribes these genes, producing an mRNA transcript. Translation of the mRNA transcript produces five enzymes that participate in a metabolic pathway that synthesizes tryptophan. Each enzyme catalyzes a different step in the pathway.